1. Field of the Invention
This invention relates to a liquid crystal display panel, and more particularly to an apparatus to select a gamma reference voltage and method of the same which is utilized by cell gap pattern to correct the gamma reference voltage.
2. Description of the Prior Art
With the development of the optical technology and the semiconductor technology, a liquid crystal display device is generally applied for consumer displays. In general, the liquid crystal display device has the advantages including high-definition, small volume, light weight, low driving voltage, low power dissipation and more applications, and thereby to be as main technology of a display device to replace conventional cathode-ray tube displays.
In general, a liquid crystal display device includes two substrates, liquid crystals sealed there-between, pixel electrode, thin film transistor configured on one substrate, color filter film corresponding to each one of the pixel electrodes and common electrode disposed on the other substrate. The color filter film consists of Red, Green and Blue three color filter films, and each one of the pixels has one of the three color filter films formed thereon. Red, Green and Blue pixel are disposed adjacent together to form one pixel.
An image is shown on a liquid crystal display panel input by an outside video data. The image is transmitted to cerebrum via eyes to reproduce the shown image, and therefore the video data transfers to Somatosensory. The video data is achieved to a direct proportion to the Somatosensory by an ideal gamma curve. The gamma curve represents as a relation between brightness and Somatosensory (gray scale) which is a non-linear relation. The liquid crystal display panel needs to be corrected gamma reference when practical gamma curve deviates from the ideal gamma curve. A gamma correction voltage is applied to liquid crystal area to alter brightness of the liquid crystal such that the practical gamma curve approaches to the ideal gamma curve, and thereby achieving a direct proportion between the video data and the Somatosensory to gain a high quality picture. In the liquid crystal display panel, gamma correction voltage is output to a driver IC of the liquid crystal display panel, and then output into the liquid crystal display panel via R-string resistor divider of the driver IC to create a required voltage for liquid rotation such that a correct picture is shown on a screen.
Currently, a gamma voltage is adjusted based-on uniform cell gap of a liquid crystal display panel. When the cell gap is not uniform owing to process factor, especially large size panel, it needs to rework for gamma voltage correction to compensate difference due to the cell gap. Moreover, a gamma voltage of a liquid crystal display panel is adjusted based-on a single point (in general set at center point) to measure brightness of gray scale for determining gamma voltage of the liquid crystal display panel. As non-uniform cell gap, a gamma voltage by signal point measuring can not been corrected the difference due to the cell gap. In manufacturing a liquid crystal display panel, if found excessive cell gap difference; it can not timely correct the gamma voltage to compensate the difference due to the cell gap.
In view of the aforementioned drawbacks, the present invention provides an improved concept without found and teaching in the prior art for efficiently resolving gamma voltage correction issue due to cell gap difference.